1. Field of the Invention
The present invention relates to an image-forming device for recording images on a recording medium by ejecting ink droplets thereonto, in which ink cartridges are detachably mounted on an ink cartridge mounting unit. More particularly, the invention relates to an ink cartridge positioning and locking mechanism for accurately positioning and fixing the ink cartridges on the ink cartridge mounting unit.
2. Description of the Related Art
Ink jet printers have been used extensively as they are simple in structure and are capable of high quality high speed printing. Typically, the ink jet printers include an ink jet head, an ink jet mounting unit, and an ink cartridge. The ink jet head ejects ink droplets onto a recoding medium to thereby form images thereon. The mounting unit supports the ink jethead and is mounted on the carriage that moves in the widthwise direction of the print paper. The ink cartridge stores ink therein and is detachably mounted on the mounting unit.
The ink cartridge is formed with an ink supply port at its bottom for supplying ink to the ink jet head. In order to mount the ink cartridge on the mounting unit, the ink supply port is firstly engaged with the corresponding part in the mounting unit, and then a locking arm swingably provided at an upper portion of the head holder is moved downward toward the ink cartridge to press the ink cartridge downward. As a result, the ink cartridge is fixedly mounted on the mounting unit.
However, the ink cartridge mounted on the mounting unit tends to move as the carriage moves back and forth at a high speed. More specifically, the ink cartridge swings or vibrates about the ink supply port in the direction in which the carriage moves, with a result that ink in the ink cartridge is shifted to one side and thus using all the ink is impossible. Provision of another locking member may prevent the ink cartridge from swinging, however, this makes the entire structure complicated and mounting and detaching operation of the ink cartridge becomes complicated.